Linux-RTC Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH] rtc: wilco-ec: Sanitize values received from RTC
@ 2019-09-10 15:19 Nick Crews
  2019-09-12  8:09 ` Alexandre Belloni
  0 siblings, 1 reply; 5+ messages in thread
From: Nick Crews @ 2019-09-10 15:19 UTC (permalink / raw)
  To: Alexandre Belloni, Alessandro Zummo
  Cc: linux-rtc, linux-kernel, Duncan Laurie, Enric Balletbo i Serra,
	Nick Crews

Check that the time received from the RTC HW is valid,
otherwise the computation of rtc_year_days() in the next
line could, and sometimes does, crash the kernel.

While we're at it, fix the license to plain "GPL".

Signed-off-by: Nick Crews <ncrews@chromium.org>
---
 drivers/rtc/rtc-wilco-ec.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-wilco-ec.c b/drivers/rtc/rtc-wilco-ec.c
index 8ad4c4e6d557..0ccbf2dce832 100644
--- a/drivers/rtc/rtc-wilco-ec.c
+++ b/drivers/rtc/rtc-wilco-ec.c
@@ -110,8 +110,16 @@ static int wilco_ec_rtc_read(struct device *dev, struct rtc_time *tm)
 	tm->tm_mday	= rtc.day;
 	tm->tm_mon	= rtc.month - 1;
 	tm->tm_year	= rtc.year + (rtc.century * 100) - 1900;
-	tm->tm_yday	= rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 
+	if (rtc_valid_tm(tm)) {
+		dev_warn(dev,
+			 "Time computed from EC RTC is invalid: sec=%d, min=%d, hour=%d, mday=%d, mon=%d, year=%d",
+			 tm->tm_sec, tm->tm_min, tm->tm_hour, tm->mday,
+			 tm->mon, tm->year);
+		return -EIO;
+	}
+
+	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 	/* Don't compute day of week, we don't need it. */
 	tm->tm_wday = -1;
 
@@ -188,5 +196,5 @@ module_platform_driver(wilco_ec_rtc_driver);
 
 MODULE_ALIAS("platform:rtc-wilco-ec");
 MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
-MODULE_LICENSE("GPL v2");
+MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Wilco EC RTC driver");
-- 
2.11.0


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, back to index

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-10 15:19 [PATCH] rtc: wilco-ec: Sanitize values received from RTC Nick Crews
2019-09-12  8:09 ` Alexandre Belloni
2019-09-15 22:44   ` Nick Crews
2019-09-16  8:02     ` Alexandre Belloni
2019-09-16 17:56       ` Nick Crews

Linux-RTC Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rtc/0 linux-rtc/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-rtc linux-rtc/ https://lore.kernel.org/linux-rtc \
		linux-rtc@vger.kernel.org linux-rtc@archiver.kernel.org
	public-inbox-index linux-rtc

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-rtc


AGPL code for this site: git clone https://public-inbox.org/ public-inbox